Modern inventory systems, such as those in mail-order warehouses, airport luggage systems, and custom-order manufacturing facilities, face significant challenges in responding to requests for inventory items. It may be particularly challenging to efficiently process operation requests that involve supply items in addition to inventory items. In inventory systems tasked with responding to large numbers of diverse operation requests, slow responses to operation requests may result in an ever-increasing backlog of operation requests. Additionally, in inventory systems where certain tasks are performed at only certain stations, overall efficiency is hampered as the rigid distribution of stations impedes throughput and adaptability.